UNIVERSITY    OF   CALIFORNIA 

COLLEGE    OF    AGRICULTURE 

AGRICULTURAL   EXPERIMENT  STATION 

CIRCULAR  No.  277 
August,  1924 

HEAD,  CANE,  AND  CORDON  PRUNING 

OF  VINES 

BY 

FREDERIC  T.  BIOLETTI  and  H.  E.  JACOB 


The  various  methods  of  pruning  vines  used  successfully  in  Cali- 
fornia may  be  grouped  into  three  general  types  for  which  head,  cane 
and  cordon  are  convenient  titles.  There  are  various  sub-types  under 
each  of  these  general  types,  each  of  which  has  advantages  for  special 
conditions.  The  types  and  sub-types  described  in  this  circular  are 
those  which  seem  most  generally  adapted  to  the  conditions  of  grape 
growing  in  California. 


HEAD  PRUNING 

The  most  usual  form  given  to  the  vine,  where  the  Vinifera  or 
European  grape  is  grown,  is  that  of  a  small  upright  shrub  (fig.  1). 
The  mature  vine  consists  of  a  vertical  stem  or  trunk  bearing  at  its 
summit  a  ring  of  arms  or  short  branches  ascending  in  the  form  of  a 
vase  or  hollow  inverted  cone.  At  the  end  of  these  arms,  at  each  winter 
pruning,  are  left  the  spurs  which  consist  of  the  basal  portions  of  canes 
which  are  the  matured  shoots  which  grew  during  the  previous  summer. 
The  point  or  region  at  which  the  trunk  divides  into  or  bears  the  arms 
is  called  the  head. 

This  method  of  training  is  often  spoken  of  as  vase  or  goblet 
pruning,  but  the  vase-formed  arrangement  of  the  arms,  though  usual, 
is  not  universal  nor  essential,  and  the  term  head  pruning  seems 
preferable. 

The  essential  points  to  be  kept  in  mind  in  developing  a  vine  of 
this  form  are : 


Z  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

THE  TEUNK 

1.  The  trunk  should  be  vertical.  This  is  necessary  to  permit  of 
close  plowing  and  cultivation  without  injury  to  the  vine ;  to  facilitate 
hoeing  and  the  removal  of  suckers  (shoots  from  below  ground)  and  of 
water  sprouts  (shoots  from  the  old  wood).  It  is  useful  also  in  the 
application  of  various  sprayings  and  treatments  needed  to  control 
mildew,  vine-hoppers  and  other  pests  and  diseases. 

2.  It  should  be  smooth,  straight  and  without  large  wounds.  This 
insures  the  health  and  long  life  of  the  vine  by  protecting  its  most  vital 
part  from  boring  insects,  decay  fungi  and  black-knot. 


at  c 

Fig.  1. — Head  pruned  vines  with  high,  medium  and  low  heads. 

3.  It  should  be  sufficiently  high  to  keep  the  fruit  from  touching  the 
ground  and,  in  frosty  locations,  to  give  the  young  shoots  some  protec- 
tion against  spring  frosts,  The  larger  and  more  vigorous  the  vine, 
the  higher  the  trunk  should  be,  especially  with  table  grapes.  (See 
fig.  1.) 

4.  To  keep  the  trunk  strong  and  healthy,  suckers  should  not  be 
allowed  to  develop.  If  removed  carefully  in  the  spring  and  early 
summer  during  the  first  three  or  four  years  they  will  cease  to  form 
and  much  troublesome  work  will  be  saved  in  future  years. 


Circular  277]      head,    CANE   AND   CORDON   PRUNING   OF   VINES  3 

If  allowed  to  grow  all  summer  or  imperfectly  removed,  they  will 
cause  the  formation  of  burls  on  the  trunk  near  and  below  the  surface 
of  the  ground.  These  sucker  burls  will  continue  to  produce  an  increas- 
ing crop  of  suckers  every  year.  If  these  suckers  are  not  removed  they 
will  take  the  upward  sap  stream  from  the  roots  and  the  top  of  the  vine 
will  finally  be  starved  or  killed. 

THE  HEAD 

1.  The  head  should  be  definite — that  is,  the  arms  should  start  as 
nearly  as  possible  from  the  same  level,  the  top  of  the  trunk.  This  is 
to  give  the  even  distribution  of  the  arms  necessary  to  insure  equal 
exposure  of  the  fruit  to  sun  and  air  and  consequent  equal  development 
of  color,  sugar  and  flavor. 

2.  This  definite  head  is  a  matter  of  gradual  development  and  is  to 
be  obtained  only  after  several  years  of  well-planned  training.  It  is 
seldom  complete  until  the  vine  is  6  or  7  years  old.  An  attempt  to 
hasten  it  will  defeat  its  own  object  and  result  in  loss  of  crop  and  in  a 
misshapen  vine. 

THE  AEMS 

1.  The  number  of  arms  should  be  sufficient  to  furnish  the  spurs 
necessary  for  the  number  of  bunches  the  vine  is  capable  of  maturing. 
This  will  vary  according  to  the  size,  vigor  and  variety  of  the  vine.  It 
may  be  only  three  or  four,  each  with  a  single  spur,  on  a  small  vine  of 
a  weak  variety,  closely  planted  in  a  soil  of  moderate  fertility.  It  may, 
on  the  other  hand,  be  six  or  seven,  dividing  into  two  or  three  at  their 
extremities,  on  a  large  vine  of  a  vigorous  variety  with  abundant  room 
in  a  rich  soil.  In  the  one  case  six  to  eight  fruit  buds  would  be  left,  in 
the  other  thirty  to  forty. 

2.  The  length  of  the  arms  will  vary  in  the  same  way  and  with  the 
same  factors.  The  point  to  be  kept  in  mind  is  that  they  should  be 
sufficiently  long  to  allow  the  bunches  room  to  develop  without  crowding 
or  interlocking.  This  is  especially  important  with  table  grapes.  This 
length  will  vary  from  five  or  six  inches  with  very  small  vines  to 
eighteen  or  twenty  with  very  large. 

3.  The  arms  originate  from  spurs  and  increase  in  length  by  the 
addition  each  year  of  a  part  of  the  spur  of  the  previous  year.  They 
require  several  years  therefore  to  reach  their  full  length  and  the 
elongation  can  be  controlled  and  adjusted  by  appropriate  pruning  to 
keep  pace  with  the  development  of  the  vine  and  the  increase  of  crop. 
Finally  when  the  vine  reaches  the  stage  of  full  bearing,  some  or  all  of 
the  arms  will  have  reached  the  length  which  is  judged  best  in  the 
particular  case.    Unless  prevented,  however,  the  arms  will  continue  to 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

elongate  and  finally  will  become  too  long  and  weak  to  support  the  crop 
and  will  be  in  danger  of  injury  in  cultivation. 

4.  Before  this  stage  is  reached,  measures  must  be  taken  to  avoid 
the  difficulty.  This  is  done  by  leaving  a  short  spur  (replacing  spur) 
suitably  placed  on  the  arm,  well  below  its  extremity.  This  spur  will 
give  rise  to  a  cane,  which  can,  the  next  year,  be  used  as  a  spur  to 
supply  fruit  and  also  to  serve  as  the  start  of  a  new  arm.  The  elongated 
part  of  the  old  arm  beyond  this  spur  is  then  removed,  leaving  in  its 
place  the  new  short  arm. 

By  this  device  applied  whenever  necessary  the  undue  elongation 
and  weakening  of  arms  can  be  avoided.  The  lower  one-third  or  so  of 
the  arm  should  be  considered  a  permanent  part  of  the  vine  in  tjie 
same  way  and  for  the  same  reasons  as  the  trunk.  The  renewal  of  arms 
therefore  should  not  extend  too  far  down. 

THE  SPURS 

1.  Each  year  the  dormant  vine  is  pruned  and  all  the  canes  produced 
during  the  last  growing  season  are  removed  entirely  except  a  few  which 
are  shortened  to  one,  two  or  three  or  rarely  more  buds.  What  is  left 
of  these  shortened  canes  constitute  the  spurs.  All  the  fruit  and  most 
of  the  growth  of  the  following  year  comes  from  the  buds  of  these  spurs. 

2.  To  preserve,  to  improve  and  to  develop  the  form  of  the  vine,  it 
is  necessary  to  make  a  wise  selection  of  canes  for  spurs. 

3.  In  varieties  suited  to  head  pruning,  any  of  the  buds  on  the  spurs 
may  be  fruitful.  Often  the  base  bud  is  sterile  and  the  first  bud  less 
fruitful  than  the  second.  From  the  second  up,  the  buds  are  usually 
equally  fruitful  where  they  are  well  formed  and  mature.  It  is  possible, 
therefore,  to  control  the  crop  within  limits,  by  the  number  of  spurs 
and  the  number  of  buds  left  at  the  winter  pruning. 

4.  A  vine  of  a  given  size  and  vigor  is  capable  of  producing  a  certain 
crop  of  good  grapes.  If  we  leave  more  fruit  buds  than  are  necessary 
for  this  crop  the  number  of  grapes  and  of  bunches  will  be  increased 
up  to  a  certain  point  but  the  quality  will  be  decreased.  If  we  carry 
this  generosity  far  enough  the  grapes  may  fail  to  develop  or  ripen  and 
the  vine  will  be  weakened  or  even  killed  by  bearing  a  large  crop  of 
worthless  fruit.  If  we  leave  fewer  buds  than  are  needed  for  the  best 
results  we  will  increase  the  size  and  quality  of  the  fruit  up  to  a  certain 
point  but  with  loss  in  quantity.  Beyond  this  point  the  crop  is 
diminished  without  any  gain  in  quality  but  the  vine  is  invigorated  by 
its  failure  to  bear  much  crop. 

5.  The  most  important  problem  of  the  pruner,  therefore,  is  to 
decide  how  many  buds  to  leave.    He  must  decide  how  many  spurs  to 


CIRCULAR  277]       HEAD,    CANE    AND    CORDON    PRUNING    OF    VINES  5 

leave  on  each  vine  and  on  each  arm  and  how  many  buds  to  leave  on 
each  spur.  Certain  general  rules  can  be  given  but  these  can  be  applied 
successfully  only  by  the  careful  observing-  pruner  with  experience  or 
expert  direction. 

6.  The  more  well  nourished  and  matured  growth  that  has  been 
made  during  the  current  season,  that  is,  the  more  vigorous  the  vine, 
the  more  good  grapes  it  is  capable  of  producing  during  the  coming 
year. 

This  rule  applies  also  to  parts  of  vines — to  each  arm  and  to  each 
spur. 

7.  The  most  useful  general  rule  for  a  pruner,  is,  first,  to  note 
whether  the  vine  shows  unusual  vigor,  medium  vigor,  or  signs  of 
weakness.  If  the  first,  more  fruit  buds  should  be  left  than  was  done 
the  previous  year ;  if  the  last,  fewer  should  be  left.  If  the  vine  seems 
of  medium  or  normal  vigor  about  the  same  number  of  buds  should  be 
left  as  were  left  at  the  preceding  pruning.  This  rule  applies  not  only 
to  the  whole  vine  but  to  individual  arms  and  spurs  and  is  independent 
of  the  causes  of  the  degree  of  vigor.  It  is,  therefore,  a  better  guide 
to  the  pruner  than  a  knowledge  of  what  the  vine  produced  the  previous 
year. 

THE  EOOTS 

1.  The  root  system  consists  of  the  main  roots  which  originate  on 
the  underground  stem  and,  passing  downwards,  divide  into  the  branch 
roots  which  in  turn  gives  rise  to  the  fibrous  or  feeding  roots. 

The  main  and  branch  roots  are  permanent  and  serve  to  conduct 
the  complementary  food  streams — the  water  and  soil  nutrients  from 
the  feeding  roots  and  the  starch  and  sugar  from  the  leaves.  New  feed- 
ing roots  are  produced  continuously  whenever  the  moisture  and  tem- 
perature conditions  are  favorable.  They  function  as  feeders  for  a 
short  time  and  then  die  or  become  part  of  the  conducting  system. 

2.  It  is  important  that  the  main  roots  be  protected  from  injury. 
This  is  possible  only  if  they  lie  below  the  depth  to  which  the  imple- 
ments of  tillage  penetrate  which,  close  to  the  vine,  is  about  four  or  five 
inches.    Koots  above  this  level  are  called  surface  roots. 

3.  If  surface  roots  are  allowed  to  remain  on  young  vines  during 
the  first  two  or  three  years  they  develop  into  main  roots  and  the  deeper 
roots  may  develop  little  or  not  at  all. 

A  vine  in  this  condition  may  grow  as  well  or  better  than  a  vine 
with  only  deep  main  roots  but  is  in  a  perilous  position.  At  any  time 
a  plow  may  strike  the  surface  main  roots,  cut  them  off  and  so  destroy 
the  whole  root  system  below  and  make  large,  jagged  wounds  in  the 
trunk. 


6  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

4.  This  danger  can  be  avoided  by  removing"  all  the  surface  roots 
during  the  first  two  or  three  years  at  the  winter  pruning".  In  this  way 
they  are  prevented  from  developing  into  main  roots  and  in  the  mean- 
while a  system  of  main  roots  is  developed  at  lower  and  safer  levels. 


a  b 

Fig.  2. — Pruning  at  planting.     Nursery  rooting  before  and  after  pruning. 

After  the  third  year,  the  vine  may  be  considered  safe  in  this  respect. 
Any  surface  roots  produced  after  this  perform  their  function  of  feed- 
ing roots  and  seldom  grow  large,  as  they  cannot  compete  with  the  large 
main  roots  already  established  lower  down.  If  these  small  surface 
roots  are  caught  by  the  plow  little  damage  is  done  as  they  constitute  a 
very  small  part  of  the  rooting  system  and  the  plow  removes  them 
without  making  wounds  in  the  main  roots  or  the  underground  part 
of  the  trunk. 


Circular  277]       HEAD,    CANE   AND   CORDON    PRUNING   of   vines 


Development  of  the  Vine 

1.  Priming  at  planting. — When  a  rooted  or  grafted  vine  is  planted, 
the  roots  should  be  shortened  to  from  two  to  four  inches  and  all  the 
new  growth  of  top  removed  except  one  cane  which  should  be  shortened 
to  two  buds.     (Fig.  2.) 

When  planted,  only  these  buds  should  show  above  the  surface  of 
the  ground.  As  a  rule  no  summer  pruning  should  be  done  and  staking 
is  unnecessary.  The  only  exceptions  to  this  are  in  some  regions  where 
the  heat,  soil  and  water  conditions  are  so  favorable  to  quick  develop- 
ment, that  the  work  of  two  seasons  can  be  done  in  one.    The  treatment 


Fig.  3.- 


First  winter  pruning,     a.  Pruning  the  top. 
suckers  and  surface  roots. 


b.  Removal   of 


in  these  cases  during  the  first  year  is  identical  with  the  treatment  for 
the  second  year  described  here  for  more  usual  conditions. 

2.  First  winter  pruning. — At  the  end  of  the  first  growing  season, 
the  young  vine  should  have  made  a  growth  above  ground  of  one  or 
more  canes  from  one  to  three  feet  long  and  a  strong  widely  spreading 
root  system. 

The  tops  are  pruned  in  winter  after  the  leaves  have  fallen.  Only 
one  cane  is  reserved  and  this  cut  back  to  two  buds.     (See  fig.  3.) 

The  vine  after  pruning,  therefore,  looks  above  the  ground  almost  as 
it  did  when  planted  the  previous  spring.  Its  condition,  however,  is 
very  different.  It  is  now  supplied  with  a  complete  root  system  and  is 
prepared  to  make  a  very  much  larger  growth  during  the  coming  season. 

Its  work  during  the  second  season  is  to  produce  a  single  strong 
cane  from  which  a  trunk  can  be  developed.    To  do  this,  it  requires  not 


8 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 


only  cultivation  and  irrigation  but  support  and  training  during  the 
spring  and  summer. 

As  soon  as  possible  after  pruning,  the  vineyard  should  be  staked 
with  3-,  4-  or  6-foot  stakes  according  to  the  height  it  is  desired  to  raise 
the  head.     (See  fig.  1.) 

"Well  before  the  vines  start  to  bud  in  the  spring,  a  single  furrow 
should  be  thrown  away  from  each  side  of  each  row  of  vines  and  the 


Fig.  4. — Second  spring  treatment — first  disbudding. 

ridge  hoed  away  for  six  inches  on  each  side  of  the  vine.  This  will 
expose  suckers  and  surface  roots  and  allow  them  to  be  removed  com- 
pletely with  a  sharp  pair  of  pruning  shears  without  leaving  stubs  to 
produce  more  suckers  and  surface  roots  the  following  years.  (See 
fig.  36.)  If  this  is  neglected  or  improperly  done  it  will  be  the  cause 
of  much  trouble  and  expense  later.  Vines  properly  suckered  and 
surface-rooted  during  the  first  two  years  give  no  trouble  in  this  respect 
later. 


CIRCULAR  277]       HEAD,    CANE   AND    CORDON    PRUNING    OF   VINES 


9 


3.  Second  summer  treatment. — In  spring,  as  soon  as  a  large  propor- 
tion of  the  vines  have  produced  a  shoot  two  to  four  inches  long,  they 
should  receive  the  first  disbudding.  This  consists  of  rubbing  off  every 
shoot  or  swollen  bud  but  the  one  which  has  grown  the  most.  (See 
fig.  4.) 


, 

I 

1 

1 

\ 

,     . 

1 

if 

Fig.  5. — Tying  the  reserved  shoot  the  second  summer. 


The  reserved  shoots  will  then  grow  rapidly  and  as  soon  as  they 
are  6  to  12  inches  long  the  vines  should  be  disbudded  the  second  time. 
This  consists  in  rubbing  off  any  new  buds  or  shoots  that  have  developed 
since  the  first  disbudding.  At  this  time,  any  vines  which  had  not 
started  before  are  disbudded  for  the  first  time.  Also  any  shoots  which 
have  grown  over  eight  inches  are  tied  loosely  to  the  stake  with  a  piece 
of  sacking  twine  or  other  soft  string. 


10  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Later,  as  soon  as  the  shoots  have  grown  12  or  15  inches  more  they 
are  tied  again  nearer  the  top  of  the  stake.  With  vines  grown  to  high 
stakes  three  or  more  tyings  are  usually  necessary.     (See  fig.  5.) 

Only  buds  and  shoots  on  the  old  part  of  the  vine  should  be  removed. 
Nothing  should  be  taken  from  the  reserved  shoot  which  is  growing. 
Secondary  side  shoots  (laterals)  will  start  on  vigorous  reserved  shoots 
in  the  angles  (axils)  where  the  leaves  are  attached  to  the  shoot.  (See 
fig.  5.)  These  should  not  be  removed.  If  any  of  these  laterals  below 
the  middle  of  the  main  shoot  show  signs  of  developing  as  rapidly  as 
the  main  shoot  they  should  be  pinched,  that  is,  an  inch  of  the  growing 
tip  should  be  pinched  off  when  they  are  12  to  15  inches  long.  (See 
fig.  5-p.) 

When  the  main  shoot  has  grown  a  few  inches  above  the  point  where 
the  head  is  desired  it  also  should  be  pinched.  This  will  tend  to 
encourage  the  growth  of  laterals.  All  laterals  on  the  upper  half  of  the 
shoot  should  be  allowed  to  grow  without  pinching  unless  they  seem  in 
danger  of  being  broken  by  the  wind,  in  which  case  they  are  pinched 
like  the  lower  laterals. 

4.  Second  winter  pruning. — Soon  after  the  leaves  have  fallen,  at 
end  of  the  second  growing  season,  the  vines  should  receive  their  second 
winter  pruning.  In  frosty  locations  it  is  better  to  defer  the  pruning 
until  a  few  days  before  the  buds  start  in  the  spring. 

Each  vine  will  consist  of  a  single  straight  cane  tied  vertically  to  the 
stake.  If  well  grown,  this  cane  should  be  cut  off  as  near  as  possible  at 
the  level  at  which  the  head  is  desired.  The  cut  is  made  through  the 
first  bud  above  the  highest  which  it  is  desired  to  have  grow.  This 
cut  is  made  in  such  a  way  as  to  destroy  the  bud  but  to  leave  the  enlarge- 
ment of  the  joint  (node).  This  is  to  facilitate  secure  tying.  (See 
%  6.) 

All  small  laterals  and  all  laterals  below  the  middle  should  be 
removed.  On  exceptionally  large  vines,  laterals  over  three-tenths  of  an 
inch  thick  on  the  upper  half  of  the  cane  should  be  cut  back  to  one  or 
two  buds,  according  to  their  strength.  These  will  act  as  fruiting  spurs 
and  help  to  develop  the  head  rapidly.     (See  fig.  6b.) 

Vines  on  which  the  cane  is  less  than  three-tenths  of  an  inch  thick 
at  the  desired  height  of  the  head  should  be  cut  back  to  two  buds  as  at 
the  first  winter  pruning.     (See  fig.  3.) 

Before  the  buds  swell  in  the  spring,  the  pruned  canes  should  be 
tied  securely  to  the  stake.  A  single  or  double  half  hitch  is  made  around 
the  cane  just  above  the  top  bud  and  the  string  tied  around  the  stake 
as  tight  as  possible  and  with  a  firm  square  knot.  (See  fig.  6.)  A  loose 
tie  is  then  placed  around  stake  and  cane  about  the  middle.     This  tie 


CIRCULAR  277]       HEAD,    CANE    AND    CORDON    PRUNING    OF    VINES 


11 


should  not  pass  around  the  cane  between  the  cane  and  the  stake,  or  the 
vine  will  be  girdled.  If  two  fingers  can  be  inserted  between  the  cane 
and  the  string  this  danger  is  avoided. 

Soon  after  the  pruned  vines  are  tied  up  and  before  the  buds  start, 
suckers  and  surface  roots  should  be  removed  thoroughly  and  carefully 
as  was  done  the  previous  year. 


Fig.  6. — Second  winter  pruning,     a.  Average  vine.     b.  Extra  vigorous  vine. 

5.  Third  summer  treatment. — During  the  second  summer,  a  cane 
has  been  produced  which  will  develop  into- tf he  permanent  trunk. 
During  the  third  summer  a  small  or  medium  crop  will  be  produced 
and  the  development  of  the  head  commenced. 

The  complete  formation  of  the  head  will  require  at  least  three 
seasons  except  under  the  unusually  intense  growing  conditions  already 
referred  to.  An  attempt  to  form  the  head  too  rapidly  will  result  in 
loss  of  crop  and  the  production  of  an  ill-shaped  vine. 

During  the  summer,  all  the  shoots  which  start  on  the  lower  third  of 
the  vine  are  removed  as  soon  as  possible  after  they  start  (see  fig.  7). 
To  allow  them  to  grow  six  or  more  inches  and  then  remove  them  stunts 


12 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


the  vine  and  delays  its  development.  All  shoots  which  start  on  the 
upper  two-thirds  should  be  allowed  to  grow  without  interference. 
Only  in  cases  where  they  grow  so  large  and  with  such  rapidity  that 
they  are  in  danger  of  being  broken  by  the  wind  should  they  be  given 


r< 


».J  •*2s&m*' 


n 


Fig.  7. — Third  summer  treatment — first  disbudding. 

any  attention.  In  this  case  it  is  usually  sufficient  to  pinch  the  tips 
when  the  shoots  are  about  eighteen  inches  long.  (See  fig.  8.)  This 
pinching  may  have  to  be  repeated. 

6.  Later  primings  and  treatments.     Formation  of  the  head. — A 
the  end  of  the  third  growing  season,  after  the  leaves  have  fallen,  an 


Circular  277]       head,    CANE   AND   CORDON   PRUNING   OF   VINES 


13 


average  good  vine  will  consist  of  a  well  developed  trunk  from  one  to 
two  inches  thick,  bearing  on  its  upper  two-thirds  from  four  to  eight 
good,  well  matured,  healthy  canes. 


Fig.  8. — Third  summer  treatment.     Second  disbudding  and  pinching. 

Enough  of  these  canes  should  be  reserved  and  cut  back  to  spurs  to 
bear  the  crop  that  the  vine  is  judged  capable  of  bearing  without  injury 
to  its  vigor  and  the  proper  maturing  of  the  grapes.  This  will  usually 
be  from  three  to  six  according  to  the  vigor  of  the  vine,  and  each  spur 
should  be  cut  back  to  two,  three  or  four  buds  according  to  its  size. 


14 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


These  spurs  should  be  as  near  the  top  of  the  vine  as  is  possible.     (See 
fig.  9a.) 

During  the  summer  no  pruning  will  be  needed  except  the  removal, 
as  soon  after  they  start  as  is  practicable,  of  all  shoots  that  start  below 
the  bottom  spur  and  of  all  suckers  that  come  from  below  ground.  A 
moderate  pinching  of  vigorous  shoots  when  they  are  18  to  20  inches 
long  may  be  necessary  in  windy  situations. 


Fig.  9. — Formation  of  the  head.     a.  Third  winter  pruning,     ft.  Fourth 

winter  pruning. 


At  the  end  of  the  fourth  growing  season  each  of  the  spurs  of  the 
last  winter  pruning  should  have  produced  one,  two  or  more  canes 
sufficiently  vigorous  to  use  for  spurs.  Commencing  at  the  top  of  the 
vine,  spurs  of  one,  two  or  three  buds  should  be  left  as  evenly  and 
symmetrically  arranged  as  possible  until  sufficient  buds  are  obtained 
to  give  the  crop  that  the  vine  is  capable  of  bearing.  All  growth  below 
should  then  be  removed.  This  will  usually  leave  all  the  spurs  on  the 
upper  third  of  the  vine.     (See  fig.  9b.) 


Circular  277]       HEAD,    CANE   AND    CORDON    PRUNING    OF   VINES  15 

The  summer  treatment  during  the  fifth  growing  season  is  identical 
with  that  of  the  fourth.  No  topping  should  be  done,  nor  even  any 
pinching,  unless  it  is  absolutely  necessary  to  prevent  serious  wind 
damage. 

The  fifth  winter  pruning  is  a  continuation  of  the  method  of  the 
fourth.  Spurs  should  be  chosen  at  the  top  of  the  vino  in  such  a  way 
as  to  give  the  head  and  arms  as  nearly  as  possible  the  open  vase  form 
and  in  sufficient  number  to  give  the  amount  of  crop  suited  to  the  size 
and  vigor  of  the  vine. 

The  vine  now  should  be  in  full  bearing  and  the  head  formed. 

The  pruning  in  later  years  depends  on  the  same  principles.  The 
number  of  buds  left  should  be  in  proportion  to  the  vigor  of  the  vine 
and  they  should  be  distributed  on  the  spurs  in  proportion  to  the  vigor 
of  the  latter.  The  distribution  of  the  spurs  should  be  such  as  to 
maintain  or  improve  the  shape  of  the  head. 

After  a  few  years  the  arms  will  tend  to  become  too  long.  This  will 
render  them  liable  to  be  injured  by  the  implements  of  cultivation  and 
make  them  weak  because  of  the  numerous  small  wounds  that  have  been 
left  in  the  annual  winter  pruning. 

When  this  stage  is  reached  it  will  be  necessary  from  time  to  time  to 
shorten  the  longer  arms.  This  is  done  by  leaving  a  replacing  spur  on 
the  arm  between  its  extremity  and  the  head  of  the  vine.  The  following 
year  the  arm  is  cut  back  to  this  spur  from  which  a  new  arm  is 
developed.  It  is  best  to  start  this  replacing  spur  one  or  two  years 
before  it  becomes  necessary  to  shorten  the  arm. 

This  can  be  done  only  if  water  sprouts  are  allowed  to  grow  on  the 
arms  during  the  summer.  It  is  nearly  always  a  mistake  to  remove  these 
water  sprouts  until  the  winter  pruning.  They  feed  and  invigorate  the 
vine  and  enable  it  to  bear  more  crop.  On  ill-shaped  vines  they  may 
grow  through  the  bunches  and  make  harvesting  difficult  without  injury 
to  the  fruit.  This  can  be  avoided,  however,  by  disentangling  the 
bunches  and  water  sprouts  early  in  the  season  when  the  grapes  are 
about  half  grown.  This  is  less  expensive  and  more  effective  than 
disentangling  them  while  harvesting. 

CANE  PRUNING 

Head  pruning  as  described  gives  good  results  only  with  varieties 
which  are  fruitful  on  the  lowest  two  or  three  buds  of  the  cane.  For 
other  varieties  pruning  back  to  spurs  of  two  or  three  buds  results  in 
small  crops  or  none  at  all,  especially  with  a  low  or  medium  trunk. 

In  these  cases  it  is  necessary  to  leave  frwit-eancs,  which  are  pieces 
of  well-ripened  canes  usually  from  2  to  4  feet  long.    The  necessity  of 


16 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


supporting  these  canes  to  keep  the  fruit  off  the  ground  and  of  supply- 
ing new  fruit  canes  from  the  head  each  year  requires  trellising  and 
several  other  changes  in  the  method  of  training. 

The  Trunk. — The  form  and  development  of  the  trunk  are  exactly 
the  same  as  for  head  pruning. 

The  Head. — The  only  difference  in  the  head  is  that  it  should  be  fan- 
shaped,  that  is  extending  in  a  plane  in  the  direction  of  the  trellis  and 
not  in  all  directions  as  in  head  pruning.  This  is  necessary  for  con^ 
venience  and  economy  of  tillage  which  can  take  place  in  only  one 
direction. 


Fig.  10. — Mature  cane  pruned  vine. 


The  Arms. — As  a  fruit-cane  bears  much  more  fruit  than  a  fruit 
spur,  fewer  are  needed  and  therefore  fewer  arms  are  necessary  to 
produce  these  canes.  Two  arms  on  each  side  of  the  head  are  all  that 
are  needed  by  a  vine  in  full  bearing.  (See  fig.  10.)  Great  care  should 
be  taken  to  keep  these  arms  in  the  line  of  the  trellis  and  not  jutting 
out  into  the  spaces  between  the  rows,  where  they  would  interfere  with 
cultivation,  make  much  hand  hoeing  necessary  to  keep  weeds  down, 
and  be  in  danger  of  damage  from  implements,  ;      . 

The  rules  regarding  the  management  of  these  arms  are  the  same 
otherwise  as  for  the  arms  of  head-pruned  vines. 

The  Fruit-Canes. — In  head  pruning,  the  spurs  have  two  functions — 
the  production  of  fruit  and  the  production  of  canes  for  the  following 
year. 

In  cane  pruning,  these  functions  are  separated.  The  fruit-cane 
bears  the  fruit  and  a  renewal  spur  is  left  to  produce  canes  for  the 
following  year.     This  renewal  spur  is  a  spur,  normally  of  two  buds. 


CIRCULAR  277]       HEAD,    CANE   AND    CORDON    PRUNING   OF   VINES  17 

one  of  which  is  expected  to  produce  a  cane  which  can  be  cut  back  the 
next  year  to  2  to  4  feet  for  a  new  fruit-cane  and  the  other  to  two  buds 
for  a  new  renewal  spur. 

Each  year  the  fruit-cane  which  has  borne  is  cut  off  and  replaced 
by  a  new  fruit-cane  from  the  renewal  spur.  In  cases  where  the  renewal 
spur  fails  to  give  suitable  canes,  canes  may  be  utilized  from  near  the 
base  of  the  fruit-cane  of  the  previous  year.  This  should  be  done  as 
seldom  as  possible,  because  it  tends  to  cause  the  arms  to  elongate  very 
rapidly.  Where  it  is  necessary  to  leave  a  renewal  spur  pointing  at 
right  angles  to  the  line  of  the  row,  it  should  be  shortened  to  one  bud. 
If  the  vine  is  vigorous,  base  buds  will  grow  and  such  a  spur  will  supply 
the  two  canes  needed. 

In  order  to  prevent  the  arms  elongating  too  rapidly,  it  is  necessary 
whenever  possible,  to  have  the  renewal  spur  nearer  the  head  of  the 
vine  than  the  fruit-cane.  Also,  replacing  spurs,  to  shorten  long  arms, 
must  be  used  occasionally  as  in  head  pruning. 

The  number  of  fruit-canes  to  leave  will  depend  on  the  size  and 
vigor  of  the  vine.  An  average  vine,  the  first  year  of  bearing,  will 
need  only  one,  with  two  or  three  renewal  spurs.  (See  fig.  11.)  The 
next  year  it  will  need  two  or  three,  with  four  or  five  renewal  spurs. 
(See  fig.  12.)  At  the  third  crop  the  vine  should  be  in  full  bearing  and 
will  need  four  fruit-canes  with  four  or  five  renewal  spurs  if  it  has 
made  the  amount  of  growth  that  it  should.     (See  fig.  10.) 

It  is  sometimes  difficult  or  impossible  to  find  well-placed  canes  for 
the  required  number  of  renewal  spurs.  This  will  not  usually  lead  to 
any  serious  defect  with  a  vigorous  vine,  as  canes  will  be  produced  from 
dormant  buds  on  the  arms  or  head.  If  the  vine  is  weak,  few  or  no 
fruit-canes  should  be  left,  and  this  will  promote  a  growth  of  suitably 
placed  shoots  from  dormant  buds. 

The  Trellis. — For  the  support  of  the  canes  and  their  crop,  a  trellis 
is  needed,  usually  of  two  wires  stretched  along  each  row  from  posts 
at  the  side  of  each  block. 

The  lower  wire  is  at  the  height  of  the  head  of  the  vine  and  the 
upper  13"  to  15"  higher.  The  fruit-canes  are  tied  horizontally  to  the 
lower  wire.  The  upper  wire  is  simply  to  support  the  shoots  from  the 
fruit-canes,  to  protect  them  from  wind  damage,  and  to  keep  the  fruit 
off  the  ground.  This  trellis  should  be  put  up  at  the  end  of  the 
first  growing  season.  (For  full  directions  concerning  trellising  see 
Circular  252.) 

As  the  fruit-canes  and  their  crop  will  be  very  heavy,  they  should 
be  tied  in  such  a  way  that  most  of  the  weight  will  fall  on  the  wire  and 
not  on  the  string  by  which  they  are  tied.  This  is  accomplished  by 
giving  the  cane  about  one  and  a  half  turns  around  the  wire  and  tying 


18 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


firmly  at  the  end.  (Figs.  11  and  12.)  No  other  tie  is  needed  in  most 
cases.  The  cane  should  not  be  twisted  several  times  around  the  wire, 
as  this  will  make  it  difficult  to  remove  at  the  following  winter  pruning. 


Fig.  11. — Cane-pruned   vine — third  winter  pruning. 


Fig.  12. — Cane-pruned  vine — fourth  winter  pruning. 


Circular  277]       head,    CANE   AND   CORDON    PRUNING   OP"    VINES  19 


Fig.  13. — High-headed  cane-pruned  vino  tied  up  for  frost  protection. 


20 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Another  Method. — A  modification  of  this  method  has  been  used 
successfully  for  vigorous  vines  growing  in  very  fertile  soil  and  is 
especially  useful  in  frosty  locations. 

A  third  wire  is  placed  about  12  inches  above  the  second,  and  the 
head  of  the  vine  is  brought  up  nearly  to  the  second  wire.  (Figs.  13 
and  14.) 


Fig.  14. — Vine  of  fig.  13  after  canes  are  tied  clown. 


The  pruning  is  exactly  the  same  as  for  the  first  method  except  that, 
being  applied  only  to  very  vigorous  vines,  somewhat  longer  canes  and 
occasionally  an  extra  one  may  be  needed. 

After  pruning,  the  fruit-canes  are  not  tied  or  are  tied  only  tem- 
porarily to  the  top  wire  as  nearly  vertically  as  possible.  This  places 
them  in  a  position  where  they  are  safer  from  frost.     (Fig.  13.)     After 


Circular  277]       HEAD,    CANE   AND    CORDON    PRUNING    OF   VINES 


21 


most  danger  of  frost  is  over,  the  canes  are  put  in  their  final  position. 
They  are  bent  over  the  middle  wire  and  tied  down  to  the  bottom  wire 
(fig.  14). 


Fig.  15. — Cane-pruned  vine  without  trellis. 

Vines  pruned  in  this  way  can  be  handled  without  a  trellis.  In  this 
case  the  canes  are  simply  bent  downward  and  tied  to  the  lower  part  of 
the  trunk   (see  fig.  15).     When  this  is  done,  renewal  spurs  are  less 


22 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


needed  as  shoots  for  the  fruit  canes  of  the  following  year  are  forced 
from  near  the  base  of  the  fruit  canes  of  the  current  year  behind  the 
bend. 

An  advantage  of  this  method  is  that  it  permits  of  cross  cultivation. 
Disadvantages  are  that  the  fruit  is  massed  together,  which  maker, 
harvesting  and  the  control  of  mildew  more  difficult,  and  the  new  shoots 
from  the  head  of  the  vine  on  which  the  crop  of  the  following  year 
depends  are  liable  to  be  broken  by  the  wind.  By  the  use  of  a  7 -foot 
stake  and  tying  the  growing  shoots  to  the  18  inches  of  stake  above  the 
head,  this  breaking  can  be  prevented  to  some  extent.     (See  fig.  15.) 


CORDON  PRUNING 

Some  varieties  do  not  give  full  crops  with  head  pruning  and  their 
fruit  is  of  inferior  size  and  quality  with  cane  pruning.  Both  of  these 
defects  can  often  be  overcome  by  cordon  pruning. 


Fig.  16. — Completed  unilateral  cordon. 

The  Trunk. — The  characteristic  of  cordon  pruning  is  that  the  vine 
is  given  a  much  longer  trunk  than  in  the  other  systems.  Instead  of 
being  2  or  3  or  at  most  4  feet  high,  it  is  extended  to  8,  10  or  more  feet ; 
and  in  the  unilateral  form  instead  of  being  vertical,  it  rises  in  a 
gentle  curve  (a  quarter  circle)  to  a  height  of  30  to  40  inches  and  then 
extends  horizontally  to  the  next  vine  (fig.  16). 

This  extension  of  the  trunk  has  the  effect  of  making  the  buds  on 
the  lower  part  of  the  canes  fruitful.  Some  varieties  which  require 
fruit-canes  with  head  pruning  bear  well  on  spurs  when  pruned  by 
the  cordon  system. 

The  length  of  the  trunk  distributes  the  crop  over  a  larger  space 
and  tends  to  keep  the  bunches  separate  from  each  other  and  from  the 


Circular  277]     head,  cane  and  cordon  pruning  of  vines  23 

shoots.  The  bunches  are  thus  more  perfect  and  can  be  more  easily 
harvested  without  injury.  The  horizontal  position  of  the  trunk  places 
all  the  bunches  at  about  the  same  distance  from  the  ground  and  makes 
possible  more  nearly  equal  uniformity  in  quality,  color,  and  time  of 
ripening. 

The  cordon  system  is  particularly  suited  to  vigorous  varieties  of 
table  grapes  which  produce  large  berries  and  large  bunches.  It 
requires  good  soil  and  abundant  water.  Weak  growing  vines  fail  with 
this  system. 

Head,  Arms,  and  Spurs. — The  vine  has  no  head  and  the  arms  are 
distributed  along  the  upper  side  of  the  horizontal  part  of  the  trunk  at 
intervals  of  10  to  12  inches.  It  is  very  important  that  the  arms  should 
all  be  on  the  upper  side ;  otherwise  the  fruit  will  be  too  low  and  finally 
lie  on  the  ground,  and  the  trunk  will  be  without  shade  and  will  be 
injured  by  the  hot  sun.  To  insure  this  requires  particular  care  during 
the  first  three  or  four  years. 

The  arms,  as  with  the  other  systems,  gradually  elongate  and  after 
several  years  must  be  replaced.  As  most  varieties  should  be  pruned  to 
short  spurs  with  this  system,  the  arms  elongate  slowly.  The  manage- 
ment of  the  spurs  is  similar  to  that  used  in  head  pruning,  except  that 
care  should  be  taken  to  have  them  as  vertical  as  possible. 

Development  of  a  Unilateral  Cordon 

The  treatment  during  the  first  year  is  exactly  the  same  as  for  the 
other  systems.  As  a  longer  and  more  vigorous  cane  is  needed  for  the 
formation  of  the  trunk,  it  is  more  often  necessary  to  cut  the  vine  back 
to  the  ground  after  the  second  as  well  as  after  the  first  growing  season 
and  to  take  three  years  to  form  the  cane  for  the  trunk. 

1.  Formation  of  the  Trunk-Cane. — At  the  end  of  the  first,  and  if 
necessary  the  second,  season  the  vine  is  reduced  to  one  cane  and  this 
cane  cut  back  to  two  good  buds  (see  fig.  3). 

A  trellis  is  then  put  up  similar  to  that  recommended  for  cane 
pruning  with  two  wires.  (See  Circular  252.)  During  the  following 
summer,  the  treatment  is  the  same  as  that  described  for  head  pruning 
up  to  the  time  the  vine  reaches  the  stage  shown  in  fig.  5c.  After  this 
stage  the  strong  laterals  are  pinched  as  shown  in  fig.  5c,  but  the  end 
of  the  shoot  is  allowed  to  grow  until  it  is  about  two  feet  above  the 
top  wire  (fig.  17a.) 

At  this  stage  all  the  ties  are  removed  except  the  lowest  at  S  to  10 
inches  from  the  ground.  The  shoot  is  then  bent  over  and  tied  loosely 
to  the  bottom  wire.  (Fig.  17b.) 


24 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


This  shoot  is  then  allowed  to  grow  and  is  tied  again  once  or  twice 
to  the  wire  as  it  lengthens.  No  tie  should  be  placed  nearer  than,  about 
15  inches  from  the  growing  tip  or  the  shoot  may  be  stunted.  If  the 
shoot  grows  long  enough,  it  is  pinched  after  it  has  passed  the  adjoining 
wire  about  a  couple  of  feet. 


a  b 

Fig.  17. — Unilateral  cordon.     Placing  the  growing  shoot  on  the  wire. 


2.  Pruning  the  Trunk-Cane  (second  or  third  winter). — At  the  end 
of  the  season,  after  the  leaves  have  fallen,  the  trunk-cane  should  be 
cut  back  to  a  place  where  it  is  at  least  half  an  inch  thick.  If  it  has 
grown  sufficiently,  it  may  be  allowed  to  extend  to  the  top  of  the  bend 
of  the  adjoining  vine.  If  it  has  not  made  a  cane  sufficiently  large  to 
reach  at  least  12  inches  along  the  wire  beyond  the  bend,  it  must  be  cut 
back  to  within  6  to  8  inches  of  the  ground  and  a  more  vigorous  cane 
grown  the  next  year.    Many  failures  are  due  to  using  small  canes. 


Circular  277]       HEAD,    CANE   AND    CORDON    PRUNING    OF   VINES 


25 


The  cane  is  then  straightened  by  turning  it  around  the  wire  from 
once  to  twice  according  to  its  length.  It  should  not  be  turned  around 
the  wire  more  than  is  necessary  to  make  it  straight,  and  in  any 
case  not  more  than  twice  and  this  only  with  canes  of  full  length.  If 
twisted  too  man^  times,  it  will  be  cut  by  the  wire  as  it  grows  and  will 
be  injured  or  broken  the  next  year  when  it  becomes  necessary  to 
untwist  it.     (Fig.  18.) 

The  end  of  the  cane  should  be  tied  firmly  to  the  wire  around  the 
stub  projecting  beyond  the  end  bud.  If  there  then  remains  any  parts 
of  the  cane  which  are  not  close  to  the  wire,  these  should  be  straightened 


Fig.  18. — Unilateral  cordon.     Trunk-cane  of  nearly  full  length. 

by  other  ties.  These  latter  ties  should  be  loose  enough  to  allow  for 
growth  of  the  cane,  which  may  reach  1  or  1%  inches  in  diameter  during 
the  summer. 

3.  First  Summer  Treatment  on  the  Wire. — During  this  season  the 
first  crop  will  be  borne  and  the  vine  will  produce  canes  from  which  to 
start  its  arms. 

Two  serious  dangers  are  to  be  avoided.  One  is  the  production  of 
too  much  crop.  This  will  result  in  grapes  of  poor  quality  and  of  no 
value  and  a  weakening  of  the  vine  which  will  prevent  it  from  pro- 
ducing the  canes  necessary  for  spurs  the  next  year.  The  other  is  the 
development  of  canes  on  the  lower  side  of  the  trunk-cane  instead  of  on 
the  upper  side. 

While  the  buds  are  starting  in  the  spring,  the  vineyard  should  be 
gone  over  several  times  and  every  shoot  starting  on  the  under  side 
of  the  cane  rubbed  off.  This  will  remove  half  the  shoots  and  leave  the 
other  half,  spaced  6  to  10  inches  apart  on  the  upper  side.  This  dis- 
budding should  be  done  as  soon  as  possible,  and  no  shoot  which  is  to 


26  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

be  removed  should  be  allowed  to  grow  more  than  about  an  inch.  At 
the  same  time  all  shoots  starting  on  or  below  the  bend  should  bo 
pinched  back,  leaving  three  or  four  leaves  on  each  to  shade  the  trunk. 
As  the  shoots  on  the  upper  side  grow  at  uneven  rates,  some  of 
them  will  soon  be  much  longer  than  the  others.  These  long  shoots  are 
usually  near  the  bend  or  at  the  end.  They  should  be  pinched  as  soon, 
as  this  can  be  done  without  injurying  the  blossom  bunch,  which  is 
usually  at  the  third  or  fourth  joint.  This  pinching  will  check  the 
growth  and  allow  the  weaker  shoots  to  catch  up  with  the  others. 
(Fig.  19.) 


Fig.  19. — Unilateral  cordon.     First  year  on  the  wire.     Shoots  ready  for 
tying  to  the  upper  wire.     Longest  shoots  ready  for  pinching. 

On  vines  which  do  not  extend  the  full  length,  a  shoot  should  bo 
allowed  to  grow  from  near  the  end  to  complete  the  trunk  and  tied 
when  long  enough  to  the  wire.  A  shoot  from  the  under  side  of  the 
cane  is  best  for  this  purpose. 

As  soon  as  the  shoots  are  sufficiently  long,  one,  two,  or  three  of 
them  should  be  tied  to  the  upper  wire.  If  this  is  not  done,  all  the  shoots 
which  start  on  the  upper  side  of  the  trunk-cane  will  turn  over  and 
their  weight,  with  that  of  the  fruit  they  bear,  will  be  so  great  as  to 
turn  the  trunk-cane  completely  over  and  leave  the  upper  side  bare 
and  the  new  canes  all  pointing  toward  the  ground.  If  this  happens 
the  vine  can  never  be  made  into  a  successful  cordon. 

This  tying  of  supporting  shoots  is  necessary  only  the  first  year 
because  the  second  year  the  trunk  is  sufficiently  thick  and  rigid  to  pre- 
vent turning.    In  very  windy  locations,  however,  it  is  useful  to  tie  the 


Circular  277]     head,  cane  and  cordon  pruning  of  vines  27 

first  strong  shoots  that  grow  along  the  trunk  even  of  older  vines  to 
prevent  breakage  by  the  wind. 

4.  Pruning  the  completed  cordons. — The  first  winter  pruning  after 
the  trunk-cane  has  been  completed  on  the  wire  consists  in  leaving  spurs 
along  the  upper  side  of  the  horizontal  trunk.  These  spurs  should  be 
spaced  about  8  to  14  inches  apart  as  evenly  as  possible.    In  case  there 


Fig.  20. — Unilateral  cordon.     Summer  treatment.     Second  summer  on  the  wire. 

is  no  cane  on  the  upper  side  where  a  spur  is  needed  a  cane  from  The 
lower  side  must  be  taken.  By  cutting  this  back  to  one  bud  a  strong 
shoot  will  be  obtained  which,  when  it  has  grown  long  enough  can  be 
tied  to  the  upper  wire  and  will  provide  a  vertical  shoot  for  the  next 
year. 

The  length  of  the  spurs  will  depend  on  the  vigor  of  the  vine  and 
of  the  cane.     It  will  vary  from  one  to  three  buds.     At  each  winter 


28 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


pruning  thereafter  a  spur  is  formed  from  a  cane  that  grew  from  the 
spur  of  the  previous  year  and,  in  time,  short  vertical  arms  will  be 
formed  along  the  top  of  the  trunk. 

These  arms  should  be  allowed  to  lengthen  gradually  until  they 
reach  the  height  considered  best,  usually  about  10  to  12  inches.  After 
this  they  should  be  shortened  by  means  of  replacing  spurs  as  witb 
head  pruning. 


Fig.  21. — Unilateral  cordon.     Winter  pruning — third  year  on  wire,  long 

or  double  pruning. 

The  completed  cordons  will  need  little  or  no  summer  pruning,  as 
is  the  case  also  with  well-formed  vines  of  any  other  system.  For  a 
year  or  two  shoots  will  form  on  the  bend  of  the  trunk  and  the  under 
side.    These  should  be  removed  early.     (See  fig.  20.) 

5.  Long  Pruning. — While  the  cordon  system  nearly  always  makes 
it  possible  to  obtain  maximum  crops  with  short  or  spur  pruning  there 
may  be  some  cases,  as  the  Ohanez  growing  in  very  rich  soil,  where  a 


Circular  277]       HEAD,    CANE   AND    CORDON    PRUNING    OF   VINES  29 

modification  in  the  direction  of  cane  pruning  might  be  advisable.  In 
such  cases  a  method  of  pruning  similar  to  that  illustrated  by  fig.  21 
can  be  adopted. 

Instead  of  spurs  of  one  to  three  buds,  canes  of  five  to  eight  buds 
would  be  left.  It  would  usually  be  necessary  to  tie  these  canes  to  the 
upper  wire. 

6.  Frost  Protection. — The  vine  shown  in  the  upper  part  of  fig.  21 
has  been  pruned  long  temporarily  as  a  measure  for  frost  protection. 
If  the  vine  is  pruned  in  this  way  during  the  winter  the  buds  at  the 
end  of  the  short  canes  will  start  at  the  usual  time  in  spring.    The  canes 


Fig.  22. — First  year  on  the  wire.     Bilateral  cordon. 

are  then  pruned  back  to  spurs  the  buds  of  which  are  dormant  and 
will  not  start  for  a  week  or  ten  days  after  the  buds  of  similar  vines 
pruned  short  earlier  in  the  usual  way. 

The  vine  shown  in  the  lower  part  of  the  figure  shows  how  this 
cutting  back  is  done.  This  is  a  useful  means  of  protection  in  frosty 
locations. 

7.  Bilateral  Cordon. — The  bilateral  cordon  consists  of  a  vertical 
trunk  rising  to  a  height  of  24  to  30  inches  and  there  dividing  into  two 
branches  which  are  conducted  horizontally  on  a  wire  at  36  to  40  inches 
from  the  ground.  The  arms  go  in  opposite  directions  and  reach  half 
way  to  the  adjoining  vine  (figs.  22  and  23). 

This  method  has  most  of  the  advantages  of  the  unilateral  and  can 
be  used  where  the  latter  is  impracticable.  A  good  unilateral  cordon 
can  be  made  only  if  it  is  started  at  the  latest  the  second  year.  A  fairly 
good  bilateral  can  be  formed  from  a  head  or  cane-pruned  vine  of  good 
form  after  the  vine  is  several  years  old.     It  also  requires  somewhat 


30 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


less  skill  and  if  found  unsuitable  can  easily  be  changed  to  the  head 
or  cane  system  by  simply  cutting  back  the  branches, 

There  is  a  tendency  with  this  system  for  one  branch  to  grow  at  the 
expense  of  the  other  but  this  can  be  controlled  by  pruning  the  spurs 
of  the  weaker  arm  shorter  and  thus  limiting  its  crop  until  it  recovers 
its  vigor. 


Fig.  23. — Bilateral  cordon.     First  or  second  summer  on  the  wire.     Long 
shoots  near  the  ends  ready  for  pinching. 

The  curves  of  the  two  branches,  going  in  opposite  directions,  result 
in  a  space  of  about  two  feet  where  there  are  no  spurs,  thus  limiting 
the  fruiting  surface.  If  spurs  are  left  on  the  curves  they  tend  to 
appropriate  the  sap  flow  and  weaken  the  arms.  The  difficulty  can  be 
overcome  by  allowing  the  first  arm  on  the  horizontal  part  of  the  branch 
to  fork  and  fill  up  the  unoccupied  space. 

In  developing  a  bilateral  cordon  the  treatment  for  the  first  three 
years  is  the  same  as  for  cane  pruning  except  that  no  renewal  spurs  are 
left  and  only  two  canes,  one  on  each  side.  These  canes  are  not  removed 
but  left  as  permanent  branches  on  the  upper  side  of  which  short  arms 
are  developed  as  in  unilateral  cordons. 


Circular  277J      HEAD,    CANE  AND   CORDON    PRUNING   OF   VINES  31 


CHOICE  OF  A  SYSTEM 

Whatever  system  we  adopt  we  must  make  our  choice  before  we 
plant  the  vineyard  if  we  are  to  obtain  all  the  benefits  of  any  system. 
The  best  number  and  arrangement  of  the  vines,  position  of  roads  and 
avenues  and  method  and  direction  of  irrigation  will  vary  according 
to  the  system  of  pruning  adopted.  (See  Circular  253,  "Vineyard 
Plans,") 

In  deciding  upon  a  system  we  should  consider  its  probable  cost 
returns  and  practicability,  as  well  as  its  suitability  to  the  variety  of 
vine,  the  soil  and  climate,  and  the  use  to  be  made  of  the  fruit. 

Cost. — The  most  economical  in  first  cost  of  stakes  or  other  supports, 
and  in  the  work  of  pruning,  tillage  and  harvesting  is  head  pruning 
Unless  the  extra  cost  is  more  than  counterbalanced  by  extra  returns 
from  the  other  systems,  head  pruning  should  be  adopted. 

Returns. — Most  varieties  give  fair  to  maximum  crops  with  head 
pruning.  With  some  varieties,  however,  the  crops  are  small  and  with 
others  the  quality  inferior  with  this  system.  For  most  wine  grapes 
and  for  the  raisin  Muscat  this  system  is  perfectly  satisfactory. 

For  certain  table  grapes,  such  as  Malaga,  Tokay  and  Black  Prince 
head  pruning  with  a  high  trunk  is  usual  and  generally  satisfactory 
though  it  is  probable  that  under  suitable  conditions  of  rich  soil,  abun- 
dant water  supply  and  hot  climate,  better  results  in  both  quality  and 
quantity  of  crop  might  be  obtained  by  the  cordon  system.  Other 
varieties  of  table  grapes,  such  as  Emperor,  Cornichon  and  Ohanez 
usually  give  poor  crops  with  head  pruning  and  require  some  form  of 
cordon  or  similar  means  of  extending  the  trunk  beyond  the  limits  of 
head  pruning.  Cane  pruning  will  increase  the  crops  of  these  varieties 
but  at  the  expense  of  quality. 

For  the  seedless  raisin  grapes,  Sultanina  (Thompson),  Sultana 
and  Black  Corinth,  cane  pruning  is  almost  always  used.  These  varie- 
ties bear  very  little  with  head  pruning  and  they  have  not  been 
thoroughly  tested  with  the  cordon  method. 

Practicability. — Head  pruning  is  the  most  commonly  understood 
and  if  improperly  or  unskillfully  applied,  the  results  are  perhaps  Less 
disastrous  than  with  the  other  systems.  However,  no  system  is  profit- 
able unless  carried  out  properly  and  if  the  owner  of  a  vineyard  will 
take  pains  to  understand  any  system  and  to  carry  it  out  properly 
there  is  very  little  more  difficulty  with  one  system  than  with  another. 


32  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Cane  pruning  perhaps  requires  the  most  experience  and  cordon 
pruning  the  least.  The  unilateral  cordon  system,  notwithstanding 
the  greater  care  and  knowledge  needed  during  the  first  three  or  four 
years,  can  be  reduced  to  a  set  of  practical  rules  to  be  followed  by  any 
intelligent  man  more  easily  than  any  of  the  others.  But  these  rules 
must  be  known  and  adhered  to. 

Suitability  to  variety. — The  general  considerations  which  should 
influence  our  choice  of  a  system  for  each  variety  have  been  discussed. 
The  following  list  of  our  commoner  varieties,  with  the  systems  of 
pruning  to  which  they  seem  most  adapted,  must  not  be  taken  as 
absolute.  Various  conditions  of  soil,  climate,  and  use  of  the  fruit 
introduce  modifying  considerations. 


SYSTEMS  SUITABLE  FOE  THE  COMMONEE  VAEIETIES  GEOWN  IN 

CALIFOENIA* 

Head  Pruning. \ — Alicante  Bouschet,  Aramon,  Black  Morocco, 
Black  Prince  (cd?),  Carignane,  Burger,  Charbono,  Chasselas  (=Gute- 
del),  Feher  Szagos,  Grand  noir,  Grenache,  Malaga  (cd),  Mataro, 
Mission  (cd?),  Mondeuse,  Muscat,  Palomino  (—Napa  Golden  Chas- 
selas) (cd),  Petit  Bouschet,  Petite  Sirah  (Duriff)  (en),  Rose  of 
Peru  (cd?),  Tokay  (cd?),  Verdal  (cd?),  Zinfandel. 

Cane  Pruning. — Black  Corinth  (=Panariti,  Zante),  Cabernet, 
Colombar  (=Sauvignon  vert)  (cd),  Semillon,  Sultana,  Sultanina 
(—Thompson)  Trousseau  (h),  Pierce  (and  nearly  all  other  Eastern 
varieties  such  as  Concord  and  Isabella. 

Cordon  Pruning. — Black  Monukka,  Cornichon,  Dattier,  Dizmar, 
Emperor,  Ferrara,  Gros  Colman  (=Fresno  Beauty,  Servian  Blue) 
(h),  Gros  Guillaume  (=Danugue)  (h),  Hunisa,  Molinera  (=Mara- 
viglia  di  Malaga,  Red  Malaga  (h),  Ohanez  (=Almeria),  Olivette 
blanche,  Prune  de  Cazoul,  Rish  Baba  (^Humphrey's  Lady  Finger), 
Zabalkanski. 

Supplementary  Information. — Circulars  245,  Pruning  Systems; 
248,  Common  Errors  in  Pruning ;  252,  Supports  for  Vines ;  253,  Vine- 
yard Plans.  For  free  copies  appty  to  the  College  of  Agriculture, 
Berkeley. 

*  Only  those  varieties  are  included  which  are  grown  in  sufficient  quantities 
to  appear  in  market  quotations. 

t  Varieties  which  do  well  under  other  conditions  are  marked:  (h)=head 
pruning;  (en)  —  cane  pruning;  (cd)  =  cordon  pruning. 

20w-9,'24 


